1. Field of the Invention
The present invention relates to a linear motor car system. More particularly, it relates to a carrier control system along a vertical conveyance path.
The linear motor car system has recently attracted favorable attention as an article conveying means because a power source need not be loaded on a carrier as a conveyor. The linear motor car system is very suitable for the transportation of small-size light-weight articles in an office, and the use of this system is now expanding.
In the linear motor car system, stator blocks of a linear motor are arranged along a conveyance path (rail). A mover of the linear motor is attached to a carrier and the carrier is placed on the conveyance path. The stators are excited to kick the mover, and in turn the carrier, so that the carrier is moved by inertia between adjacent stators. When the carrier arrives at the subsequent stator, the stator is excited to kick the carrier. And thus, the stators are sequentially excited to move the carrier to its destination on the conveyance path.
Such linear motor car system is used, for example, as a cash conveyance system between a window and a cash handling part in a bank. If the window and the cash handling part are on the same floor of a building of the bank, the conveyance path can be substantially horizontal as a whole, although certain undulations in the path are inevitable. But, if the window and the cash handling part are located on different floors, a vertical conveyance zone is included in the conveyance path.
2. Description of the Related Art
In a conventional linear motor car system, the conveyance path is generally arranged in a substantially horizontal plane, including certain inevitable undulations, but it is not applied to a portion including a large vertical distance, for example, a distance extending from the first floor to the second floor of a building. If the conveyance path is arranged on a long, gently inclined plane, a large vertical distance can be covered, but the space required is increased. Accordingly, a steep inclination is preferred and a vertical path is especially preferred. As the vertical delivery means, conventionally a vertical moving system is often adopted wherein a rack-pinion system or a chain-belt system is used.
In this conventional system, however, different types of driving are necessary for the horizontal conveyance zone and vertical conveyance zone, respectively, and the structure becomes complicated either mechanically or electrically. Furthermore, in the vertical conveyance zone, the carrier is once stopped, then raised or brought down and started again. Accordingly, a time loss is inevitably incurred.